こうですか
https://paiza.io/projects/d7NlACCEu8-hpXIg9EXIBw
import time
prev = 0
for i in range(500):
t = time.time()
u = int((t - int(t)) * 100000)
if prev != u:
print(f'{i:03} {u:06}')
prev = u